We wish to study the mechanism involved in the induction of ornithine decarboxylase (ODC) in normal and neoplastic cells. For these studies, we plan to use normal liver cells (primary cultured hepatocytes) and cultured Reuber H35 hepatoma cells. Work done in this and other laboratories indicates that cyclic AMP (cAMP) may mediate the induction of ODC in many important rapid growth systems. By incubating both cell types with increasing doses of a cAMP analogue (DBcAMP) and glucagon, we intend to elucidate the series of biochemical events which lead via a transcriptional mechanism to the induction of ODC. Using omega-aminoalkyl agarose chromatography, we will monitor the sequential activation of type I and type II isozymes of cAMP-dependent protein kinase. We intend to investigate the specific activation and turnover of the kinase isozymes in relation to ODC induction and to the regulation to normal liver and hepatoma cell proliferation. An affinity chromatography procedure will be developed in order to identify and purify specific nuclear proteins which serve as substrates for the cAMP-dependent protein kinases. We hope to determine how this activation and subsequent specific phosphorylation of nuclear proteins may lead to the control of ODC induction. Particular emphasis will be placed upon comparing the mechanism(s) involved in this induction in the H35 cells to those present in the primary cultured hepatocytes. Since ODC and cAMP have been shown to be closely related to a variety of growth processes, we feel that this aspect of our study may offer particular merit in elucidating the process of neoplasia.